Kirill/simplexml — pull request #1 by dvorkin (2011-10-26 14:14:52+00:00)
Title: Correct reading nulls from XML file

Library unloads 'null' variant values as '{{null}}' string. But it can't load this string as null value back. It loads this string as an ordinary string value.
Problem is solved by add new function:
function GetVarVal(aValue: TXmlString): Variant;
This function is used in
procedure TXmlNode.SetAttr(const aName, aValue: TXmlString);
and
procedure TXmlNode.SetAttr(aNameID: Integer; const aValue: TXmlString);

Signed-off-by: Andrey Matveev